Thanks for sharing this. A few comments though:
1) the drawback of this install is that you cannot pair other devices to it without removing the back panel
2) no auto connect (you already mentioned and the work around)
3) you cannot plug in other devices to 3.5mm jack. I mean you can but I wouldn't recommend it unless can if you want the opamps to fight
4) If the car has 6FL option (USB/Ipod adapter) there are easier ways to integrate bluetooth
5) Have you tried removing 2 caps on AUX board? If not you should and comment back on sound quality changes.
BTW you could have soldered the cables directly to PCB without using RCA connectors. I guess you did it for convenience factor in case you want to pull the BT receiver out.

It has auto connect and multilink (you can have 2 phones connected at the same time and switch between them).
In my car it was easy as I have 6FL (USB and aux in center console). I added a small usb hub and plugged in usb flash drive and BT adapter (for power). And then connected 3.5mm cable to Aux jack.
My wife's car like yours doesn't have the 6FL option. So I simply ran the wire to the aux jack and plugged adapter into usb charger connected to cigarette lighter outlet behind the glove box. I plan to tap to AUX and cigarette lighter like you did and run the wires to the center console.

1) the drawback of this install is that you cannot pair other devices to it without removing the back panelSure you can. My wife brings her phone into the car and pairs it right up. I also haven't noticed an issue of the two phones fighting to pair when we're both in the car since you have to initiate a pair up "manually."

3) you cannot plug in other devices to 3.5mm jack. I mean you can but I wouldn't recommend it unless can if you want the opamps to fightI had half a mind to fill the plug with epoxy. If I had a blanking plate, it would be gone. I made a sincere effort to use the 3.5 cord with my phone for a few days. It's such a safety hazard and the tendency of unpredictable sound due to plugs getting tweaked or partially pulled out is simply not worth the effort.

5) Have you tried removing 2 caps on AUX board? If not you should and comment back on sound quality changes.It's on my todo list, but it sounds pretty darned good. I've got a CD with the same mp3 tracks as are loaded on my phone. Tonal sound is quite similar, though the gain is a little higher on the CD.

1) the drawback of this install is that you cannot pair other devices to it without removing the back panelSure you can. My wife brings her phone into the car and pairs it right up. I also haven't noticed an issue of the two phones fighting to pair when we're both in the car since you have to initiate a pair up "manually."

3) you cannot plug in other devices to 3.5mm jack. I mean you can but I wouldn't recommend it unless can if you want the opamps to fightI had half a mind to fill the plug with epoxy. If I had a blanking plate, it would be gone. I made a sincere effort to use the 3.5 cord with my phone for a few days. It's such a safety hazard and the tendency of unpredictable sound due to plugs getting tweaked or partially pulled out is simply not worth the effort.

5) Have you tried removing 2 caps on AUX board? If not you should and comment back on sound quality changes.It's on my todo list, but it sounds pretty darned good. I've got a CD with the same mp3 tracks as are loaded on my phone. Tonal sound is quite similar, though the gain is a little higher on the CD.

1) There is a difference between connect and pairing. Let me explain this. You typically engage pairing mode by pushing the button and then your bluetooth device become discoverable (shows up on the BT device list on your phone and is ready to pair). You only pair device once and from there on you only connect to your phone. I looked at the picture of the adapter you bought and I don't see a push button. This probably means it is in discoverable mode all the time, that is it always shows up on the BT list of the device you haven't pair it with.
Now if that is the case than it is a great advantage of this setup over tons of others.

3) AUX input may not be as convenient or safe to use while driving, though it offers better sound quality (assuming you are using decent phone) and doesn't have latency associated with BT A2DP. When I go with my wife shopping I ended up sitting in the back seat watching movies on my tablet (it fits perfectly between front seats on the center console). I use Android tablet and players that allow me to fix lipsync problem (BT latency), though if I was to grab my wife's Ipad instead I don't know if she has any video players that will allow me to control audio delay (XBMC certainly does but requires a jailbroken ipad/iphone and may not be the best player from battery life point of view). There is really no fix if you are streaming directly from the web site though, the lip sync problem is always there.

5) I have yet to remove those caps on my car with 6FL option. I need to figure out a way to fish it out. BTW the nice thing about CIC is that you can adjust the gain on AUX input to match CD or whatever source you use (SAT/RADIO).

1)...This probably means it is in discoverable mode all the time, that is it always shows up on the BT list of the device you haven't pair it with. Now if that is the case than it is a great advantage of this setup over tons of others.Yep, that's it.

3) AUX input may not be as convenient or safe to use while driving, though it offers better sound quality...I have a Samsung Galaxy Note 3 with aptX built in, and the BT receiver I'm using has aptX on board too. The sound quality issues would start with BMW's wiring and audio components in regards to SQ.
This will address the latency issue and compare between aptX and other inferior BT codec technologies

aptX® has been the best kept secret of the professional audio industry for many years. Now music lovers can enjoy the rich listening experience that only aptX® can deliver: pure wireless sound that doesn’t compromise on audio quality.

aptX® technology is at the heart of the best devices from leading brands such as Sony, Samsung, Vizio and Panasonic.

1)...This probably means it is in discoverable mode all the time, that is it always shows up on the BT list of the device you haven't pair it with. Now if that is the case than it is a great advantage of this setup over tons of others.Yep, that's it.

3) AUX input may not be as convenient or safe to use while driving, though it offers better sound quality...I have a Samsung Galaxy Note 3 with aptX built in, and the BT receiver I'm using has aptX on board too. The sound quality issues would start with BMW's wiring and audio components in regards to SQ.

aptX® has been the best kept secret of the professional audio industry for many years. Now music lovers can enjoy the rich listening experience that only aptX® can deliver: pure wireless sound that doesn’t compromise on audio quality.

aptX® technology is at the heart of the best devices from leading brands such as Sony, Samsung, Vizio and Panasonic.

I work with CSR so I am familiar with their low latency solutions. The problem is that no major players have adopted this format. The implementation of APT-X you see nowdays gives you better sound quality (some Android phones), with Apple devices you typically send AAC (which is even better in case when you stream music downloaded from itunes as no additional reincoding has to take place). On my older phone (HTC Sensation) with custom ROMs loaded I was able to get APT-X working without paying the royalty which I successfully confirmed with Bluetooth Air Traces. No BT adapter will improve the sound quality of well implemented analog out in the configuration we are discussing here (Analog input on BMW). This is easy to verify by switching between your phone audio and BT.

It surely looks like they have released different versions of this module.
Parts express sells Bluetooth 2.1 and so does the ebay seller you've purchased from.
Your last link to share electronics has Bluetooth 4.0 and aptX version.

You can also find these 2 different versions on amazon sold by Sure Electronics at higher prices.